학술논문
Small u(κ) at singular κ with compactness at κ++.
Document Type
Article
Author
Source
Subject
*CARDINAL numbers
*TREES
*
Language
ISSN
0933-5846
Abstract
We show that the tree property, stationary reflection and the failure of approachability at κ + + are consistent with u (κ) = κ + < 2 κ , where κ is a singular strong limit cardinal with the countable or uncountable cofinality. As a by-product, we show that if λ is a regular cardinal, then stationary reflection at λ + is indestructible under all λ -cc forcings (out of general interest, we also state a related result for the preservation of club stationary reflection). [ABSTRACT FROM AUTHOR]